Authors: Xin Gang Li, Zhen Qing Wang, Ze Yong Chen, Li Min Zhou, Kang Yang
Abstract: This is an experiment of the damage examination of plate material with the application of elastic waves. By use of two ultrasonic probe attached to the surface of plate material, elastic waves can be injected into the structure and the probe can also receive the echo signal. By comparing the received echo signal of the defect structure and of an intact structure, the purpose of recognizing the existence of defects was achieved by extracting the signal reflection caused by the defective components. A comprehensive research based on ultrasonic wave for nondestructive testing experimental system was done. The Ultrasonic flaw detector produces high–frequency and high–voltage pulse signals and it stimulates the actuators to transmit the elastic waves into the plate material. Another probe receives the echo signals, and as to the diagnosis of the extraction of the echo signal, a good method will be adopted: By the method of continuous wavelet transform, and then study the distribution of time domain and frequency domain. By comparing echo signal, the purpose of identifying the existence of defects is achieved by extracting the echo signal caused by the defective components.
349
Abstract: Scattering of SH-wave by a semi-cylindrical hill above a subsurface elastic cylindrical inclusion in half-space is studied by complex variable function. Firstly, the whole solution domain is divided into two parts, and the solutions that satisfied the boundary conditions are constructed in two parts respectively. Then according to the “conjunction” condition of junction interface and the boundary condition around the subsurface elastic cylindrical inclusion, a set of infinite algebraic equations about the problem can be obtained. Finally the computational results of surface displacement were provided and discussed.
4037
Authors: Jiang Chang, Xue Gong, Zhi Hui Sun
Abstract: In this paper the vibration testing and Fast Fourier Transform(FFT) analysis detection on the basis of nondestructive testing method were analyzed. The dynamic Young’s modulus of the regeneration pre-sensitized offset plate were obtained by using the nondestructive testing methods, including the dynamic Young’s modulus by longitudinal vibration method, the dynamic Young’s modulus by out-plane flexural vibration method, and the dynamic Young’s modulus by in-plane flexural vibration method. The linear correlativity was investigated between the dynamic Young’s modulus and the modulus of elasticity(MOE) for the regeneration pre-sensitized offset plate.The linear correlations between the dynamic Young’s modulus and the MOE were good. So it is feasible to predict and analyze the plate mechanical properties put forward the nondestructive testing method of key mechanical performance parameters.
348
Authors: Shi Lun Feng, Pu Lin Li, Jun Li, Yuming Zhou
Abstract: The finite element method has been used widely in foundation pit engineering to simulate the deep foundation excavation, but it is troublesome and time-consuming to get the important calculation parameter of the soil elastic modulus. So a method based on the comon soil parameters is proposed to get the soil elastic modulus. And a real foundation excavation was simulated using the finite element software ABAQUS and the soil elastic modulus got according to the proposed method. The three-dimensional finite element analysis results were compared to the field data, and both results were close to each other.
386
Authors: Wen Qing Wu, Xue Yuan Ma, Shuai Chen
Abstract: The compressive mechanical performance of bamboo strip plywood was studied in the paper. Based on analysis of the related experiments datum , the principal compressive mechanical performance under static load were expounded perfectly, and a number of mechanical parameters such as compressive strength, compressive elastic modulus and compressive constitutive relations were obtained. It was shown that the mechanical performance of bamboo strip plywood was better than that of wood material such as Northeast larch, the compressive elastic modulus was lower than that of concrete, so that there existed a more great deformation when the bamboo beam structure was loaded, and the constitutive relations of bamboo materials showed that there was excellent ductility with an obvious characteristic of plastic deformation . This research result showed that there was a great significance on studying and application of bamboo bridges in the future.
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